TUMOR OF DISTAL TIBIA - MASQUERADING AS TENOSYNOVITIS IN AN ELDERLY FEMALE - A CASE REPORT

Dr Stani Mathew; Dr Lawrence Mathias

Volume : IX, Issue : I, January - 2020

TUMOR OF DISTAL TIBIA - MASQUERADING AS TENOSYNOVITIS IN AN ELDERLY FEMALE - A CASE REPORT

Dr Stani Mathew, Dr Lawrence Mathias

Abstract :

INTRODUCTION : Primary bone lymphoma is a rare disease, accounting for about 3% of all primary bone malignancies in adults. Patients with primary NHL of bone commonly present with local bone pain, soft tissue swelling, and a mass or a pathological fracture. There is a slight male preponderance, and most patients are over 45–50 years of age. Primary NHL of bone can arise in any part of skeleton, but long bones (femur) is the most common sites of presentation but distal tibia is an unusual,rare site of presentation. The outcome of patients with primary lymphoma of bone is relatively favorable with multidrug regimen chemotherapy +/– radiation therapy CASE PRESENTATION : A 50 year old female presented with chief complaints of pain and swelling over the left leg since 2 months, which was insidious in onset , gradually progressive in nature and with low grade intermittent fever since 1 month. There was no preceding history of trauma, joint stiffness or other associated constitutional symptoms. She had an episode of enteric fever 2 months ago, which was treated with IV antibiotics. She gives history of chemo–radiation for oral malignancy 17 years back, the details of which were not available to us at presentation. She has also undergone hysterectomy 14 years back, following which she had no complications. On general examination, patient had stable vitals, with no pallor or generalised lymphadenopathy. She had left sided non–pitting pedal edema upto the level of mid–calf. On examination of the right leg, we found that she had multiple localized swellings noted over the distal third of leg. The skin over the swelling was normal, with no wounds, scars, sinuses or dilated veins over the leg. On palpation, there was local rise of temperature with tenderness over the left leg swelling. The swelling had a smooth surface with ill–define margins, soft in consistency with no evidence of crepitus or abnormal movements. Peripheral pulsations were well palpated, and there was no sensory or motor deficits. On movement of left ankle joint, the terminal movements were painful and restricted.Patient was investigated further, where routine blood investigations and X–rays were done, which were found to be inconclusive.MRI of right leg was done to rule out soft tissue infections or osteomyelitis – which revealed a large infiltrative soft tissue lesion over the ankle and lower one third of right leg encasing the tendons, distal tibia and fibula , muscles, skin and subcutaneous tissue with cortical erosions and marrow edema in distal tibia and fibula. A differential diagnosis of synovial sarcoma or metastasic lesion to distal tibia/fibula was suggested based on the MRI report.In view of features suggestive of metastasis, oncology opinion was sought, where they advised USG abdomen and pelvis & chest x–ray.USG abdomen and pelvis was suggestive of bilateral metastases to adrenal glands with retroperitoneal lymphadenopathy. To confirm the same, CECT abdomen and pelvis , with thorax screening was ordered. This revealed multiple retroperitoneal enlarged lymp nodes with multiple metastases to adrenal and kidneys. Hence, we considered a possibility of lymphoma based on these finding.For the purposes of staging, bone marrow aspiration and biopsy was done, which was found to be normal.With all preliminary investigation done to diagnose the primary lesion, it was decided to perform a biopsy of the lesion from left distal tibial metaphysis and soft tissue swelling.Histopathology revealed a lympho proliferative lesion suggestive of Non Hodgkin`s Lymphoma.Immunohistochemistry markers were ordered on the histopathology specimen, which showed positivity for CD 45, CD 20 , Ki 67 and was confirmed to have Diffuse Large B cell Lymphoma.Patient was then referred to the Oncology department for chemotherapy. Patient is on regular follow–up since then, and remains asymptomatic. CONCLUSION: Primary lymphoma of the bone involving distal tibia is a very rare entity, with chemotherapy and radiotherapy being the mainstay of treatment. Surgery has a limited role.Early diagnosis and treatment can help reduce significant morbidity and mortality.